The PNP suspects that a sexually active adolescent has pityriasis rosea. Based on the differential diagnosis, the PNP screens for:

The PNP suspects that a sexually active adolescent has pityriasis rosea. Based on the differential diagnosis, the PNP screens for:

• A. Chlamydia
• B. Secondary syphilis
• C. Erysipelas
• D. Molluscum contagiosum

Answer: (B)

When a sexually active adolescent presents with a rash that could be pityriasis rosea, the key concept is that secondary syphilis can mimic pityriasis rosea. Pityriasis rosea typically starts with a herald patch and then a trunk-centered, mild, self-limited rash. Secondary syphilis, however, can produce a generalized maculopapular eruption that may involve the trunk and sometimes the palms and soles, and it can be accompanied by mucous patches, lymphadenopathy, or other systemic symptoms. Because syphilis is sexually transmitted and can have significant health implications if missed, it’s important to screen with serologic testing (non-treponemal like RPR or VDRL, followed by confirmatory treponemal testing) in this context. Other conditions listed don’t align with the presentation. Chlamydia typically presents with mucous discharges or cervicitis/urethritis rather than a diffuse pitriasis rosea–appearing skin eruption. Erysipelas is a acute bacterial skin infection with a well-demarcated, painful, often fiery-red plaque and systemic symptoms. Molluscum contagiosum shows discrete, pearly papules with central umbilication, not a widespread trunk-predominant rash.

When a sexually active adolescent presents with a rash that could be pityriasis rosea, the key concept is that secondary syphilis can mimic pityriasis rosea. Pityriasis rosea typically starts with a herald patch and then a trunk-centered, mild, self-limited rash. Secondary syphilis, however, can produce a generalized maculopapular eruption that may involve the trunk and sometimes the palms and soles, and it can be accompanied by mucous patches, lymphadenopathy, or other systemic symptoms. Because syphilis is sexually transmitted and can have significant health implications if missed, it’s important to screen with serologic testing (non-treponemal like RPR or VDRL, followed by confirmatory treponemal testing) in this context.

Other conditions listed don’t align with the presentation. Chlamydia typically presents with mucous discharges or cervicitis/urethritis rather than a diffuse pitriasis rosea–appearing skin eruption. Erysipelas is a acute bacterial skin infection with a well-demarcated, painful, often fiery-red plaque and systemic symptoms. Molluscum contagiosum shows discrete, pearly papules with central umbilication, not a widespread trunk-predominant rash.